Specific heat of low-T-c Tl2Ba2CuO6+delta

A sensitive differential ac technique has been used to measure the specific heat of low-T-c single-crystal T(l)2Ba(2)CuO(6+delta)(T-c approximate to 15 K) in fields up to 7 T applied parallel to the c axis. In contrast to high-T-c cuprates where a magnetic field substantially broadens the resistive transition, in these low-T-c samples, the field simply shifts the transition to lower temperatures leaving its width unchanged. Our specific-heat results, however, show a quite different behavior. The superconducting anomaly is dramatically reduced in size and broadened by the field, suggesting, in analogy with other cuprates, the presence of strong thermal-fluctuation effects.